KodeCloud CKAD Commands and Arguments

Links: 111 KodeCloud Index

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Commands & Arguments

• In case of ENTRYPOINT in docker whatever CMD you specify, it will get appended to ENTRYPOINT command.

• In case of CMD the command line instruction will get replaced entirely whereas in case of ENTRYPOINT the command line parameters will get appended.

  • 

• Pod definition with ENTRYPOINT and CMD

  apiVersion: v1
  kind: Pod
  metadata:
      name: ubuntu-sleeper-pod
  spec:
      containers:
       - name: ubuntu-sleeper
         image: ubuntu-sleeper
         command:
          - "sleep2.0"
         args: 
          - "10"
  

In the above example command is equivalent to the ENTRYPOINT instruction in the Dockerfile and the args is equivalent to the CMD instruction

• The commands and args must be in quotes.

• In general I have only seen the use of command and not args in a definition file.

  apiVersion: vl
  kind: Pod
  metadata:
      name: ubuntu-sleeper-pod
  spec:
      containers:
       - name: ubuntu-sleeper
         image: ubuntu-sleeper
         command:
          - "sleep2.0"
          - "10"
  

• Questions: Find the command being run assuming the pod is created from the image of Dockerfile.

  • Question 1:
    • 
    • python app.py --color pink
  • Question 2:
    • 
    • --color green

Basically command overrides the entrypoint of Dockerfile

• Commands is an array so they can also be given in the following way

  apiVersion: v1
  kind: Pod
  metadata:
      name: ubuntu-sleeper-pod
  spec:
      containers:
       - name: ubuntu-sleeper
         image: ubuntu-sleeper
         command: ["sleep", "10"]
  

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Last updated: 2023-05-03